Flexible staybolt construction for boilers



1936. G. P. ROBINSON I FLEXIBLE STAYBOLT CONSTRUCTION FOR BOILERS FiledSept. 28, 1955 -FIG. 2:-

lllll Patented Jan. 21, 1936 UNITED STATES j PATENT OFFICE FLEXIBLESTAYBOLT CONSTRUCTION FOR BOILERS Application September 28, 1935, SerialNo. 42,580

'1 Claims.

- This invention relates to improvements in flexible stayboltconstructions for boilers.

The object of the invention is to devise a flexible stayboltconstruction of a special but wellknown type, hereinafter moreparticularly referred to, that is of simple, compact and comparativelycheap construction, is comparatively cheap in maintenance and sure inoperation.

The type of staybolt construction to which the present invention appliesis that in which the staybolt is known as the flexible tell-tale holebolt having the tell-tale hole extending through the bolt longitudinallythereof and open at its outer or head end.

In the accompanying drawing Figure 1 is a central longitudinal sectionalview-of a staybolt construction embodying the present invention, securedto the boiler sheets fragmentally shown in section, the bolt being shownin elevation; Fig. 2 is an elevation of the staybolt assemblage; andFig. 3 is a top plan view of the staybolt assemblage. I

The tell-tale hole employed in 'staybolts is for the purpose ofdetecting defective bolts either while the boiler is in use or duringtimes when the boiler is being tested for defective bolts. It istherefore essential that the tell-tale hole be maintained free fromforeign matter and especially be free from foreign matter prior to atest. There are several well-known ways of testing the telltale hole toascertain if it is satisfactorily open or free from foreign matter priorto making a boiler test, but where the tell-tale hole extends entirelythroughout the bolt from end to end and is open at both ends it iscomparatively easy to make this test for all that is necessary is topass a wire from the inner end of the bolt through the'hole to the outerend. It is this type of bolt that is employed in the present invention.

Describing now a preferred embodiment of the invention, a boltassemblage, indicated generally by the reference character A, is shownin Fig. 1 as connected to the boiler in the usual manner. The assemblagecomprises a sleeve 1 engaging a hole 2 formed in the outer plate 3 ofthe boiler and secured thereto by means of a weld 4. A seat 5 is formedon the inner wall of the sleeve and threads 6 are provided around theupper end of the outer face of the sleeve. The staybolt proper isdenoted by the reference numeral 1. A spherical head 8 is formed on theouter end of the bolt 1, the head being disposed within the sleeve withits spherical surface engaging the seat in the usual manner to providefor the bolt 1 a flexible connection with the sleeve. Threads usualmanner. The head end of the bolt is pro- 5 vided with diametricallydisposed slots l3 for the application of a tool to facilitate screwingthe bolt into the inner boiler sheet II in the usual manner.

As thus far described the staybolt construction fo is of' ordinarydesign, and while the sleeve is shown as provided'with a seat forreceiving the bolt head, the invention is intended to cover structureswherein the seat is formed in the boiler plate and the sleeve is setupon the outer face of 1'5 the boilerplate, as shown for instance in thereissue patent to Mennie, 14,796, Fig. 2 thereof. Furthermore, while awelded-on sleeve is shown, it will be understood that a threaded-onsleeve or any other appropriate sleeve may be used, 20 if desired.

A cap M is secured to the sleeve l, threads l5 being formed on the innerwall of the cap for this purpose, which are screwed upon the threads 6formed on the sleeve, the cap being provided with a hexagonal outersurface Hi to facilitate screwing it upon the sleeve. The sleeve and capprovide a housing for the spherical bolt head. An opening I! is providedin the cap and a plug I8 is secured in the opening. Preferably threadsl9 are provided on the wall of the opening and threads 20 on the plug,as the means for securing the plug to the cap, the threads of the plugbeing screwed into the threads of the cap, and the plug having its outerend squared, as shown at 2 I, to facilitate screwing it into the cap.

The bolt 1 is provided with the usual tell-tale hole 22 open at the heador outer end, as indicated at 23, and at the inner end, as indicated at24, where it communicates with the firebox in the usual manner althoughthe hole at this inner end may be temporarily closed, during service inthe usual way if desired. A hole 25 extends longitudinally throughoutthe plug in line with the hole 22, and is open at its outer end to theexterior.

A diaphragm 26 is disposed across the housing, having itsouter peripherysecured to the wall of the housing and its central portion in engagementwith the end of the bolt, this central portion being provided with anorifice 21 which affords communication between the holes 22 and 25. Asshown in thepreferred embodiment, the outer periphery of the diaphragmis disposed between the upper face of the sleeve and the lower face ofthe cap, whereby by tightly screwing the cap upon the sleeve a seal isefiected between the diaphragm and sleeve at the outer periphery of theformer.

The plug I8 has its inner end pressing against screwing the plugsufficiently tight upon the dia-.

phragm. Furthermore in the present preferred embodiment the end of thebolt at the head end thereof is formed spherically convex, as shown at28, the center at of the sphere being preferably coincident with thecenter of the spherical head of the bolt. The diaphragm isformed'cup-shape to provide .a centrally disposed socket 29, the bottomof the socket (which is the central portion of the diaphragm) beingspherically shaped to correspond to the spherical shape 28 of the end ofthe bolt. The plug l8 has its inner end extending within the socket, theend wall thereof being spherically concave, as indicated at 3|],complementary to the spherically convex surface 28. The spherical jointthus provided between the diaphragm and bolt head permits of a rotatableslidable relative movement therebetween, although it will be appreciatedthat in actual practice this m'ovement is very slight.

The plug may be screwed into the cap the required extent to produce thedesired squeeze of.

the diaphragm between the-plug and the bolt head. The cup-shape giventhe diaphragm enables the end of the plug to snugly fit the side wallsof the socket thus provided and to thereby best support the centralportion of the diaphragm so that the bolt head may slide relativethereto in a practical manner under the maximum permissible pressurefrom the-plug without unduly pulling on the diaphragm at its outerperiphery and without endangering the seal thereby. Furthermore, theangular shape given the diaphragm provides ample material in thediaphragm so that the plug may move the middle portion of the diaphragmtoward the bolt head to the desired extent without interfering with theseal at the periphery of the diaphragm. Furthermore, the diaphragm beingbacked up by the cap and plug throughout substantially its entire area,it is well supported against any excessive pressure that mightaccumulate within the housing between the diaphragm and bolt head.

While the preferred design of diaphragm and plug have been shown anddescribed, it will be understood that it is not intended to therebylimit the scope of the invention, and other andvariously shapeddiaphragms and plugs may be' employed that provide the required tightfit between the diaphragm and bolt head. Therefore it will be understoodthat many and various changes and modifications in form, structure andarrangement of these parts as well as the various other parts of theconstruction may be made Without departing from the spirit of thepresent invention, and that all such changes and modifications arecontemplated as a part of the present invention as defined by theappended claims.

The invention claimed and desired to be secured by Letters Patent is:

1. The combination-oi a boiler wall member; a housing member, one ofsaid members having a seat, said housing member comprising a sleevesecured to said wall member and a cap secured to said sleeve andprovided with an opening; a plug secured in said opening, having a holeextending therethrough open at the outer end to the exterior; a bolthaving a head in flexible engagement with said seat and a longitudinalhole open at said head end; and a diaphragm extending across saidhousing with its outer periphery sealed to the wall or" said housing,its central portion engaging said bolt and provided with an orificeaiTording communication between said holes, said plug having its innerend pressing against said diaphragm portion thereby holding said portiontightly against said bolt in relative slidable engagement therewith.

2. A staybolt construction comprising a housing formed of a sleevehaving a seat, and a cap, secured to the sleeve, having an opening; abolt having a head flexibly engaging said seat and a longitudinal holeopen at the head end; a plug secured in said cap opening having a holeextending therethrough open at the outer end to the exterior; and adiaphragm extending across said housing with its outer periphery sealedto the wall of said housing, its central portion engaging said bolt andprovided with an orifice affording communication between said holes,said plug having its inner end pressing against said diaphragm portion,thereby holding said portion tightly against said bolt in relativeslidable engagement therewith.

3. A staybolt construction comprising a sleeve having a seat; a bolthaving a head flexibly engaging said seat and a longitudinal hole openat the head end; a cap secured to said sleeve having an opening; a plugsecured in said opening, having a hole extending therethrough open atthe outer end to the exterior; and a diaphragm extending across saidsleeve with its outer periphery secured between said sleeve and saidcap, its central portion engaging said bolt and provided with an orificeaffording communication between said holes, said plug having its innerend pressing against said diaphragm portion, thereby holding saidportion tightly against said bolt in relative slidable engagementtherewith.

4. A staybolt construction comprising a housing formed of a sleevehaving a seat, and a cap, secured to the sleeve, having an opening; abolt having a head flexibly engaging said seat and a longitudinal holeopen at the head end; a plug secured in said cap opening having a holeextending therethrough open at the outer end to the exterior; and adiaphragm extending across said housing with its outer periphery sealedto the wall'of said housing, its central portion cupped to form a sockethaving a bottom in engagement with said bolt and'provided with anorifice affording communication between said holes, said plug having itsinner end extending into said socket pressing against said bottom,thereby holding said bottom tightly against said bolt in relativeslidable engagement therewith.

5. A staybolt construction comprising a hous ing formed of a sleevehaving a seat, and a cap, secured to the sleeve, having an opening; abolt having a head flexibly engaging said seat and a longitudinal holeopen at the head end, the end of said bolt at said head end beingspherically convex; a plug secured in said cap opening having a holeextending therethrough open at the outer end to the exterior; and adiaphragm extending across said housing with its outer periphery sealedto the wall of said housing, its central portion engaging said sphericalend of said bolt, and spherically shaped correspondingly, and providedwith an orifice afiording communication between said holes, said plughaving its inner end concave complementary to said spherical endpressing against said diaphragm portion, thereby holding said portiontightly against said bolt in relative rotatable slidable engagementtherewith.

6. A staybolt construction comprising a housing formed of a sleevehaving a seat, and a cap, secured to the sleeve, having an opening; abolt having a head flexibly engaging said seat and a longitudinal holeopen at the head end, the end of said bolt at said head end beingspherically convex; a plug secured in said cap opening having a holeextending therethrough open at the outer end to the exterior; and adiaphragm extending across said housing with its outer periphery sealedto the wall of said housing, its central portion cupped to form a sockethaving a bottom in engagement with said spherical end of said bolt, andspherically shaped correspondingly, said bottom being. provided with anorifice affording communication between said holes, said plug having itsinner end extending into said socket, concave complementary to saidspherical end and pressing against said diaphragm portion, therebyholding said portion tightly against said bolt in relative rotatableslidable engagement therewith.

7. The combination of a boiler wall member; a housing member, one ofsaid members having a spherically concave seat, said housing membercomprising a sleeve secured to said wall member and a cap secured tosaid sleeve and provided with an opening; a bolt having a sphericallyconvex head in flexible engagement with said seat and a longitudinalhole open at said head end, the end of said bolt at said head end beingspherically convex, the centers of said spherical head and saidspherical end of said bolt coinciding; a plug secured in said capopening, having a hole extending therethrough open at the outer end tothe exterior; and a diaphragm extending across said housing with itsouter periphery sealed to the wall of said housing, its central portionengaging said spherical end of said bolt, and spherically shapedcorrespondingly, and provided with an orifice afiording communicationbetween said holes, said plug having its inner end concave complementaryto said spherical end pressing against said diaphragm portion therebyholding said portion tightly against said bolt in relative rotatableslidable engagement therewith.

GARLAND P. ROBINSON.

